Best First(Locally Bought) Mountain Bike For The Money?

I've been riding road bikes for a couple years now and living so close(4 miles) to the mountain trails and not having mountain bike just seems silly to me. I'm 6' and ride a 56cm Fuji road bike. I'm looking in the $600 range in the local adds and come across these 4 bikes. If you were me which bike would you have? People around here who ride the trails say the most you will need for these trails are a short travel full suspension. I'm really fine with anything but I wouldn't know any better. Tell me what you think!

At 6', you are a bit on the tall side for a medium frame -- which is what a couple of those bikes look like ----- The rentals from Napa can be had in your size, but they look like they are specced cheaper ---- That Focus would be a nice deal (if it were a Large --- being hunched over with the seatpost extended past max will get old eventually )